Decouple PowerUsageMonitor{Impl} from //content/browser

chrome/browser/chrome_browser_main.cc

Index: chrome/browser/chrome_browser_main.cc
diff --git a/chrome/browser/chrome_browser_main.cc b/chrome/browser/chrome_browser_main.cc
index 6e3e14b2cc96c364e574a4d97e1b5cb07c1a5512..76e769b8f79aeb88e8804ed333f07e7c6e6b325e 100644
--- a/chrome/browser/chrome_browser_main.cc
+++ b/chrome/browser/chrome_browser_main.cc
@@ -76,6 +76,7 @@
 #include "chrome/browser/performance_monitor/performance_monitor.h"
 #include "chrome/browser/plugins/plugin_prefs.h"
 #include "chrome/browser/power/process_power_collector.h"
+#include "chrome/browser/power_usage_monitor/power_usage_monitor_impl.h"
 #include "chrome/browser/prefs/chrome_command_line_pref_store.h"
 #include "chrome/browser/prefs/chrome_pref_service_factory.h"
 #include "chrome/browser/prefs/incognito_mode_prefs.h"
@@ -153,7 +154,6 @@
 #include "content/public/browser/notification_registrar.h"
 #include "content/public/browser/notification_service.h"
 #include "content/public/browser/notification_types.h"
-#include "content/public/browser/power_usage_monitor.h"
 #include "content/public/browser/site_instance.h"
 #include "content/public/common/content_client.h"
 #include "content/public/common/content_features.h"
@@ -1932,7 +1932,7 @@ int ChromeBrowserMainParts::PreMainMessageLoopRunImpl() {
   browser_creator_.reset();
 
 #if !defined(OS_LINUX) || defined(OS_CHROMEOS)  // http://crbug.com/426393
-  content::StartPowerUsageMonitor();
+  PowerUsageMonitor::StartPowerUsageMonitor();

[blundell, 2016/10/27 21:21:55]

I think this could just be owned directly by ChromeBrowserMain now.

[ke.he, 2016/10/28 09:39:20]

Done.
The original implementation of this StartPowerUsageMonitor() uses the
"LazyInstance" to create the PoowerUsageMonitor object, because it is in content
layer and has the thread safe consideration. Now we move it into
ChromeBrowserMain, so we don't need to create in the "LazyInstance" way.
blundell@, Is it ok? thanks!

 #endif  // !defined(OS_LINUX) || defined(OS_CHROMEOS)
 
   process_power_collector_.reset(new ProcessPowerCollector);